The relationship of lateral release and tourniquet deflation in total knee arthroplasty.

A total of 242 knees in 198 patients undergoing total knee arthroplasty were reviewed to evaluate the effect of tourniquet deflation on lateral release rates, possible variables associated with the need for lateral release, and adequacy of intraoperative evaluation on final radiographs. The need for lateral release was determined using the "no-thumbs" and "full contact" rules and visual evaluation. Lateral release was performed after tourniquet deflation. A total of 171 (71%) knees needed a lateral release before tourniquet deflation. After tourniquet deflation, only 53 (22%) required lateral release, representing a 69% reduction. Obesity was the only other significant factor in lateral release requirement. Based on the observations of this study, it is recommended that the need for lateral release be evaluated after tourniquet deflation. A 69% reduction in lateral release supports the hypothesis that tourniquet pressure has an effect on patellar tracking. Lateral release appears to be effective in restoring normal patellar tilt, and obesity increases its need.